Method and device for introducing samples into chromatographic columns

ABSTRACT

A method and device for introducing into a chromatographic column a sample held in a cartridge. The cartridge is placed on a carrier which is then placed between a valve casing and a superimposed spring-loaded pressure head. The valve in the casing is adjusted to pass eluate from a pump directly into the chromatographic column thereby bypassing the cartridge. The cartridge is then tightly clamped between the pressure head and the valve which is adjusted to pass eluate from the pump through the pressure head and through the cartridge into a chromatographic column.

United States Patent [72! Inventor Jiri Hrdina Prague. Czechoslovakia 21 Appl, No 814,290

[22] Filed Apr. 8, 1969 [45] Patented Sept. 14, 1971 [731 Assignee Ceskoslovenska Akademie Ved Praque, Czechoslovakia [32] Priority Apr. 9, 1968 1 33 1 Czechoslovakia [54] METHOD AND DEVICE FOR INTRODUCING SAMPLES INTO CHROMATOGRAPIIIC COLUMNS 5 Claims, 3 Drawing Figs.

[521 US. Cl 73/422 GC [51] Int. Cl G0ln H00 [50] Field of Search 73/421, 23, 23.1, 53, 61 .1 C; 23/230, 253

[56] References Cited UNlTED STATES PATENTS 2,833,151 5/1958 Harvey 73/422 GC 3,119,251 1/1964 Bowers 73/422 GC X 3,249,403 5/1966 Bochinski et al. 73/422 GC X 3,282,651 11/1966 Ferrari et a1. 73/423 A X 3,487,678 l/1970 Thomson et a1. 73/422 GC X FOREIGN PATENTS 1,507,455 12/1967 France 73/422 GC Primary Examiner-S. Clement Swisher Attorney- Paul H. Smolka ABSTRACT: A method and device for introducing into a chromatographic column a sample held in a cartridge. The cartridge is placed on a carrier which is then placed between a valve casing and a superimposed spring-loaded pressure head. The valve in the casing is adjusted to pass eluate from a pump directly into the chromatographic column thereby bypassing the cartridge. The cartridge is then tightly clamped between the pressure head and the valve which is adjusted to pass eluate from the pump through the pressure head and through the cartridge into a chromatographic column.

PATENTED SEP 1 4 I97! SHEET 1 OF 3 H DINA NV l'OR.

Armmr METHOD AND DEVICE FORINTRGD UCING SKM PLES INTO CIIROMATOGRAPIIIC COLUMNS My present invention relates to a method of introducing samples into chromatographic columns for chromatographic analysis. The invention also relates to a device for carrying out this method.

In one of such known methods sample vessels are in troduced one after the other into hydraulic circuits and the samples are forced by switching valves to progressively enter the columns. Such devices are however very complicated thus leading to high building and maintenance costs and to a possible reduction in the reliability of the operation.

In another known method the individual samples intended to be analyzed are intercepted in a number of ion exchangers arranged between two porous plates in individual thimbles or cartridges. These cartridges, of which a great number may be employed, are progressively introduced into a place where at the the beginning of the analysis of each sample the respective cartridge is compressed from above by a pressure body which introduces elution solutions from a pump. In this known method at the beginning of an analysis and during its entire duration each individual cartridge is also pressed to the mouth of the upper closure of the column. In this manner each individual cartridge during the analysis of a sample which has been introduced therein becomes part of the hydraulic circuit of the column.

The drawback of this known method resides in the fact that the pump of the elution must be stopped before the analysis of another sample located in another cartridge can be started. Then a practical disappearance of the pressure on the column has to be awaited, whereupon the pressure of the pressure body is released and the cartridge which has to be placed out of function is replaced by another one. After such replacement follows a lowering of the cartridge carrier and an actuating of the pressure body. Only then the pump can be started creating a stream of liquid in the chromatographic column. This causes three drawbacks:

First, time is lost between the stopping of one analysis when the pump is practically at rest and the restarting of the analysis when the pump is again set into operation;

Second, the ion exchanger or another column charge is exposed to pressure changes from a maximum operational pressure down to zero pressure when a cartridge is changed. This drawback would not be very serious in older processes where the mechanical properties of the column charges were rather high. But in modern highly effective chromatographic processes the mechanical properties of the column charges are the main limiting factors. The limited strength and progressing permanent deformation of the grains of the column charge causes a progressive increase in the hydraulic resistance, and thus also in the pressure, until quite inadmissable values are reached which lead to complete blocking of the passage, particularly if the column charge is subjected to pressure changes as is necessarily the case in the ab ven ne known method of introducing a sample in the columns;

The third drawback resides in the fact that it is not possible to start a new analysis or regeneration and restabilization after a preceding analysis. It is thus not possible to achieve the advantages of partial overlapping of the individual analyses, as is advantageously achieved with the device in accordance with the invention.

It is therefore a general object of the invention to eliminate the above-mentioned drawbacks. By eliminating the necessity of interrupting the passage through the column when changing a sample the invention permits not only the use of substantially higher operational pressures without danger of blocking the passage through the column but it also eliminates entirely any loss of time when changing cartridges. The invention also permits performance of a new analysis in the upper part of the column already at a time when in the lower part of the column apreceding analysis or its regenerative or restabilization phase is being terminated. These two advantages are very important in modern analyzers of various mixtures, particularly physiological mixtures or mixtures of amino acids which are becoming more important in fundamental and. applied research, operational controls etc.

The application of the method and device in accordance with the invention permits an increase in the effectiveness of analyses even if many samples are automatically introduced for individual analyses occurring one after the other, the increase in the efficiency being more than twice the maximum of the efficiency attainable up to the present. For example, if an analysis taking place for about 2 hours or slightly less is considered to be a maximum effect, the same separation may be achieved in less than half this time using the method and device in accordance with the invention.

Another important advantage resides in the fact that the cartridge holding the sample which is being analyzed may be released after a very short time since the sample has left it after the start of the analysis and this or any other cartridge located in a common carrier need not be part of the hydraulic circuit even in the case of automatic analysis of any sample. In addition, requirements for sealing the cartridges are less difficult in view of the relation of the time required for removing a sample to the total time required for the analysis. I

The main feature of the invention resides in the fact that the samples which are placed on the chromotographic columns in advance in at least one sample vessel are mechanically transposed with this vessel between the mouth of the supply pipe for the pressure elution liquid and a hydraulic bypass valve with at least two operational positions; in its first operational position this hydraulic valve connects during the first and second operational step the supply of the elution liquid supplied by a pump directly with the chromatographic column while the mouth of the inlet of the pressure elution liquid which is connected by means of a pipe with the hydraulic valve is without hydraulic communication with the pump during these two operational steps.

Thus the invention includes a device to carry out my new method. This device comprises a hydraulic valve with a rotary valve member in at least two operational positions. In its first position the valve member connects the discharge pressure pipe of the elution pump directly with a capillary duct leading the elution liquid into the chromotographic column, and in its second position connects the pump with a pipe leading the elution liquid from the pump to a moveable pressure member which may be hydraulically tightly pressed to the sample vessel or cartridge thereby pressing the cartridge against a capillary duct in the hydraulic switch. This duct is connected in this second functional position of the hydraulic switch with a capillary duct or a pipe leading the elution liquid into the column.

In accordance with another embodiment the device comprises a hydraulic valve with a spindle and two ducts in the same plane at right angles to the axis of the spindle. One of these two ducts opens on the circumference at points which are end arcs of a larger arc than the are between the mouths of the second duct, this second are between the mouths of the duct having the same angular dimension as the distance of one mouth of the duct from the other mouth of the duct.

In accordance with the invention another embodiment the device in accordance with the invention comprises two ducts in different planes at right angles to the axis of the spindle, and a body with ducts which, in one position of the spindle secure simultaneously the flow of the eluent through one path to the column and in the second position, they secure a direct flow of the eluent through a second path to the column.

The above and other features and objects of the invention will be best understood from the following specification to be read with the accompanying drawing in which FIG. 1 is a cross-sectional view of the device in accordance with the invention,

FIG. 2 shows in a cross-sectional view another position of the device illustrated in FIG. I, and

FIG. 3 suggests in a perspective view another embodiment of the device.

The device illustrated in FIGS. 1 and 2 comprises a hydraulic valve composed of a stationary valve casing 1 and a rotary valve member 2 which is reciprocatable by the attached lever 5 between a first position as shown in FIG. 1 and a second position shown in FIG. 2.

A pump 6 forces an elution medium into the column 4 either directly as shown in FIG. I over the conduits 7, 8, 9, 10, 11, thus bypassing the sample holding cartridge 3, or as shown in FIG. 2 through one of the properly positioned sample holding cartridges 3 over the conduits 7, 8, 9, l2, 13, 14', 17, 9', I0, 11.

A plurality of cartridges 3 is supported by the longitudinally or circularly moveable carrier 16 to position successive cartridges 3 in alignment with the entrance duct 17. The carrier 16 is also reciprocable in vertical direction as indicated by the appended double arrow to displace the aligned cartridge 3 into and out of communication with the sample entrance duct 17 in valve casing 1. A superimposed pressure head 14 which rests in the stationary support 18, is loaded by spring and presses the aligned cartridge 3 against the entrance duct 17, as shown in FIG. 2. The pressing force is governable by adjusting means such as screw 18'.

In the first position shown in FIG. 1 the pump 6 forces an elution medium through tubing 7 into elution medium entrance duct 8 in the valve casing 1 and through the cranked joining duct 9 in the rotary valve member 2 into column duct 10 in the valve casing 1 from where the elution medium enters the column 4 through tubing 11. In this position no cartridge 3 communicates with pump 6.

In the second position shown in FIG. 2 one of the sample holding cartridges aligned with the sample duct 17 is lowered to tightly communicate therewith and is secured in this position by the superimposed pressure head 14 described above. The elution medium flows from pump 6 through the conduits 7, 8, 9, and from the valve casing through the elution medium exit duct 12, and then through the flexible tube 13, the cranked duct 14 in the lower portion of pressure head 14 into and through the cartridge 3 to pass into duct 17 through duct 9' in valve member 2 into duct 10 and thereafter through conduit 11 column 4. The sample in cartridge 3 contained therein in liquid state is simply carried into the column 4 by the flow of the elution medium; if the sample is absorbed in an ion exchanger within the cartridge 3 elution is already accomplished therein. In any case the period while the device is in the second position shown in FIG. 2 is very short in relation to the period required by the entire analysis. The transfer of cartridge 3 from position shown in FIG. 1 into position shown in FIG. 2 occurs while elution medium is driven by pump 6 directly into column 4 as shown in FIG. 1.

In operation, assuming that the cartridge is aligned with the duct 17 and the sample has been carried from the cartridge 4 into the column 4, the cartridge 3 is released from engagement with the duct 17 and is in the position shown in FIG. 1. The carrier 16 then moves toward the right, as viewed in FIG. 1, until the next cartridge 3 is aligned with the duct 17. The rotary valve 2 is in the position shown in FIG. 1, so that fluid from the pump 6 is conducted through the passage 9 to the column 4. When the carrier 16 has moved the next cartridge into alignment with the duct 17, the head 14 moves downwardly relative to the support 18 and the carrier 16 also moves downwardly until the lower end of the cartridge 3 engages the entrance to the duct 17 and the lower end of the head 14 is received in the socket at the top of the cartridge 3, as shown in FIG. 2.

When the sample in the cartridge is to be carried into the column 4, the valve lever 5 is adjusted manually to the position shown in FIG. 2, so that eluent fluid is conducted through the tube 13 and through the bore in the cartridge 3 to carry the sample through the passage 9' in the valve 2 and into the column 4. After an appropriate time interval, the valve 5 is returned to the position shown in FIG. 1 to shut off flow of eluent liquid through the cartridge and to conduct eluent directly to the column. The carrier 16 and the head 14 then move upwardly to release the cartridge 3 from engagement with the valve body 1. There is sufficient time to replace one cartridge with another while eluent fluid is being conducted to the column 4, so that the process need not be interrupted to permit the changing of sample cartridges.

FIG. 3 illustrates in substantially perspective side view another embodiment of the device for carrying out the method in accordance with my invention. Therefore in FIG. 3 some parts are illustrated as directly viewed in a transparent body. Any other suitable material may be used for making the valve casing 19.

The valve casing 19 comprises a horizontal rotary valve member 20 equivalent to member 2 in FIGS. 1 and 2. It contains two mutually parallel ducts 21 and 22 perpendicularly passing the longitudinal axis of member 20. These ducts 21,22 are illustrated by dotted lines in a vertical position, and by stippled lines in a position turned through 60 in clockwise direction. The valve member 20 does not directly sit in the body 19 but in bearing bushes 23 and 24 made for example of polytetrafluorethylene. These two, bearing bushes are distanced by a tubular spacer 25. They may be axially pressed in by a ring 26 by a screw 27 tightened by an outer head 28. The valve casing 19 of the hydraulic switch comprises a vertical and inclined ducts 31, 33, 34, 36 as illustrated.

In the position in which the rotary valve member 20 is turned so that the ducts 21,22 are in the stippled inclined position the elution liquid passes through an inlet needle 29 and the duct 30 into the inclined duct 31, then through the inclined duct 22 in valve member 20 into the twice-cranked duct 32, thereafter through the inclined duct 21 in valve member 20 into the inclined ducts 33 and 34, and hence through vertical duct 35 directly into the column 4.

The functions of the before mentioned elements are entirely similar to the equivalent elements described with reference to FIGS. 1 and 2. The outer elements of the device such as the pump 6 and the pressure overhead 14 are not illustrated to simplify the showing. After turning the rotary valve member 20 into a position in which the ducts 21,22 are in the dotted vertical position, the above-described bypass circuit is interrupted and the elution solution flows from the duct 30 through the inclined duct 36 and the continuing vertical duct 37 into the duct 22 in the rotary valve member 20. Then the elution liquid continues to pass through the cranked duct 38 arranged in the valve casing 19 and enters the outlet needle 39 connected over tubing 13 with the not shown pressure body 14 in accordance with FIG. 1. The cartridge 3 is only partially shown in FIG. 3. The eluent carrying a mixture of materials from cartridge 3 intended for analyzing enters the upper vertical duct 40. The cartridge 3 includes elements tightly connecting it to the duct 40. Among these elements is a resilient ring 41 surrounding the hollow needle 42 which is screwed into the casing 19. Thus in the vertical position of the ducts 21,22 the elution liquid passes into the column 4 from cartridge 3 through the aligned vertical ducts 41,21 and 35. Except for the differences in the valve body 19 and the associated ducts, the embodiment of FIG. 3 operates in substantially the same manner as that of FIG. 1 and 2.

Having shown and described two embodiments of my invention to illustrate the application of the principles thereof, it will be understood that my invention may be otherwise embodied without departing from said principles and without avoiding the scope of the appended claims.

1. An apparatus for continuous liquid chromatographic analysis said apparatus comprising:

A. a chromatographic column;

B. a pump for supplying liquid elution medium to the chromatographic column;

C. a plurality of cartridges each adapted to contain a sample to be analyzed in the chromatographic column;

D. means for alternatively directing the elution medium from the pump either:

1. directly to the top of the chromatographic column or,

2. to one of the plurality of cartridges to remove the sample contained therein and then to the top of the chromatographic column,

B. said means for directing the elution medium comprising a valve having a valve casing and a rotatable member therein, said valve casing having an elution medium entrance duct, an elution medium exit duct, a sample entrance duct, and a column entrance duct, the rotatable valve member having passages therein arranged when in a first rotational position to connect the elution medium entrance duct with the elution medium exit duct and simultaneously connect the sample entrance duct with the column entrance duct, in the second rotational position of said valve member, said passages connect the elution medium entrance duct directly to the column entrance duct, while interrupting the flow between said sample entrance duct and said column entrance duct.

2. The apparatus of claim 1 further comprising a pressure head, and means for clamping one of the cartridges between the pressure head and said valve casing conduit means for conducting elution medium from said exit duct to said pressure head, said one cartridge being in fluid communication with said sample entrance duct while clamped in order to permit the passage of the elution medium through the cartridge while maintaining the elution medium under pressure.

3. A device for introducing into chromatographic columns a sample held in a longitudinal passage of at least one cartridge comprising in combination:

a pump for supplying an elution medium;

a chromatographic column;

valve means including a valve casing and a rotary valve memberreversibly displacable therein about an axis of rotation between a first position and a second position;

a carrier for the cartridge, said carrier being moveable relative to the valve casing;

a spring-loaded pressure head movable to clamp a cartridge between said valve casing and said pressure head;

a first duct in the valve casing passing eluate in the valve member's first position from the pump means directly into the column avoiding the cartridge; and

a second duct in the valve casing passing eluate in the valve members second position from the pump means to the pressure head and through the clamped cartridge into the column, said valve member having first and second valve passages arranged in parallel in a plane containing the axis of rotation of the rotary valve member; and a system of entrance and outlet ducts in the valve casing adapted to cooperate with said parallel valve passages so that in the first position of the valve means the elution medium flows directly from the pump means into the column and in the second position flows through the tightly clamped cartridge into the column.

4. The apparatus of claim 3 wherein the samples are each contained in a vertically mounted capillary passage in each cartridge.

5. The apparatus of claim 3 wherein the samples are absorbed on an ion exchanger held within each cartridge. 

1. An apparatus for continuous liquid chromatographic analysis said apparatus comprising: A. a chromatographic column; B. a pump for supplying liquid elution medium to the chromatographic column; C. a plurality of cartridges each adapted to contain a sample to be analyzed in the chromatographic column; D. means for alternatively directing the elution medium from the pump either:
 1. directly to the top of the chromatographic column or,
 2. to one of the plurality of cartridges to remove the sample contained therein and then to the top of the chromatographic column, E. said means for directing the elution medium comprising a valve having a valve casing and a rotatable member therein, said valve casing having an elution medium entrance duct, an elution medium exit duct, a sample entrance duct, and a column entrance duct, the rotatable valve member having passages therein arranged when in a first rotational position to connect the elution medium entrance duct with the elution medium exit duct and simultaneously connect the sample entrance duct with the column entrance duct, in the second rotational position of said valve member, said passages connect the elution medium entrance duct directly to the column entrance duct, while interrupting the flow between said sample entrance duct and said column entrance duct.
 2. to one of the plurality of cartridges to remove the sample contained therein and then to the top of the chromatographic column, E. said means for directing the elution medium comprising a valve having a valve casing and a rotatable member therein, said valve casing having an elution medium entrance duct, an elution medium exit duct, a sample entrance duct, and a column entrance duct, the rotatable valve member having passages therein arranged when in a first rotational position to connect the elution medium entrance duct with the elution medium exit duct and simultaneously connect the sample entrance duct with the column entrance duct, in the second rotational position of said valve member, said passages connect the elution medium entrance duct directly to the column entrance duct, while interrupting the flow between said sample entrance duct and said column entrance duct.
 2. The apparatus of claim 1 further comprising a pressure head, and means for clamping one of the cartridges between the pressure head and said valve casing conduit means for conducting elution medium from said exit duct to said pressure head, said one cartridge being in fluid communication with said sample entrance duct while clamped in order to permit the passage of the elution medium through the cartridge while maintaining the elution medium under pressure.
 3. A device for introducing into chromatographic columns a sample held in a longitudinal passage of at least one cartridge comprising in combination: a pump for supplying an elution medium; a chromatographic column; valve means including a valve casing and a rotary valve member reversibly displacable therein about an axis of rotation between a first position and a second position; a carrier for the cartridge, said carrier being moveable relative to the valve casing; a spring-loaded pressure head movable to clamp a cartridge between said valve casing and said pressure head; a first duct iN the valve casing passing eluate in the valve member''s first position from the pump means directly into the column avoiding the cartridge; and a second duct in the valve casing passing eluate in the valve member''s second position from the pump means to the pressure head and through the clamped cartridge into the column, said valve member having first and second valve passages arranged in parallel in a plane containing the axis of rotation of the rotary valve member; and a system of entrance and outlet ducts in the valve casing adapted to cooperate with said parallel valve passages so that in the first position of the valve means the elution medium flows directly from the pump means into the column and in the second position flows through the tightly clamped cartridge into the column.
 4. The apparatus of claim 3 wherein the samples are each contained in a vertically mounted capillary passage in each cartridge.
 5. The apparatus of claim 3 wherein the samples are absorbed on an ion exchanger held within each cartridge. 